Shower gels, body washes, cleansing lotions, liquid soaps, and the like (hereinafter collectively referred to as “liquid cleaning compositions” be they liquids, gels, lotions or foams) have grown increasingly popular in recent times. Such compositions typically comprise a mixture of surfactants as skin cleaning agents. The performance of these compositions can be modified by modifying the interaction of the surfactants in the mixed surfactant system.
It is known to use salts to modify the packing of surfactants to achieve higher viscosity. See, e.g., Lin et al., “Spherical-To-Wormlike Micelle Transition In CTAB Solutions”, J. Phys. Chem., 1994, 98, 5984-5993 and Yang, “Viscoelastic wormlike micelles and their applications”, Current Opinion in Colloid & Interface Science 7 (2002) 276-281. With the addition of increasing concentrations of salt, the viscosity typically increases, reaches a maximum, and suddenly decreases. This observation is related to the formation of dense wormlike micelles (tighter packing which results in high viscosities) and then branched wormlike micelles (which causes the viscosity to drop).
However, high levels of salt cause the cleaning product to be stringy, and adversely affect the foam properties of the product.
It is therefore desired to increase the viscosity of liquid cleaning compositions and to create different compositional forms.